Postpartum Stressful Life Events and Intimate Partner Violence as Risk Factors for

Self Reported Postpartum Depression among American Indian / Alaska Native

MothersMaria N. Ness, M.P.H

Kenneth D. Rosenberg, M.D., M.P.H.Office of Family Health, Oregon Public Health Division, Portland, OR

Victoria Warren-Mears, Ph.D., R.D., L.D.Thomas M. Weiser, M.D., M.P.H.

Northwest Portland Area Indian Health Board, Portland, OR

Council of State and Territorial Epidemiologists Annual ConferenceJune 14, 2011

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Background: Postpartum Depression (PPD)

• Maternal depressive disorder occurring after pregnancy

• Very common, estimated that 10% to 15% of women in developed countries experience PPD

• Period of increased risk from birth of child to two years postpartum

• Other than direct effects on the mother, PPD impairs maternal role function, which can adversely affect the child, short or long term

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Background: PPD among American Indian/Alaska Native (AI/AN) Women• Very little research examining PPD in AI/AN

communities• Prevalence of PPD higher among AI/AN

mothers than among general population• Studies have found prevalence of PPD as high

as 23% among populations with a high proportion of AI/AN women

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Research Question• Developed in conjunction with the Northwest

Portland Area Indian Health Board• Triggered by reports of high prevalence of

SLEs and IPV among AI/AN mothers• Research Question: Are postpartum stressful

life events (SLEs) and intimate partner violence (IPV) risk factors for postpartum depression among AI/AN mothers in Oregon?

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Data Source: PRAMS-2

• Oregon’s Pregnancy Risk Assessment Monitoring System (PRAMS) follow-back survey

• Conducted when index child is two years old• Data collected in 2006 and 2007• N = 1,911 women of all race/ethnicities• n = 226 AI/AN women

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Self Reported PPD in PRAMS-2• Self reported depressive symptoms 13 to 24

months postpartum examined using a two part question:In the past 12 months, has there been a period of 2 or

more weeks when almost every day you:a) Felt sad, blue, or depressed for most of the day

(Y/N)b) Lost pleasure or interest in most things you usually cared about or enjoyed (Y/N)

• Mothers who answered yes to either part of this question were considered to be experiencing PPD*

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*Prevalence of self-reported postpartum depressive symptoms--17 states, 2004-2005. Centers for Disease Control and Prevention (CDC). MMWR Morb Mortal Wkly Rep. 2008 Apr 11;57(14):361-6.

Categorization of SLEs

• PRAMS-2 asks mothers to report SLEs experienced 13 to 24 months postpartum

• SLEs from PRAMS categorized in previous studies, these were adapted to SLEs reported in PRAMS-2

• Four categories of SLEs used, adapted from categories used by Ahluwalia et al, 2001*:– Partner related– Traumatic– Financial– Emotional

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*Ahluwalia, Indu B., et al (2001) “Multiple Lifestyle and Psychosocial Risks and Delivery of Small for Gestational Age Infants”, Obstetrics & Gynecology, Vol 97, No. 5, Part 1, pg. 649-656

Categorization of SLEs, cont.

Category Specific SLEs

Partner-relatedSeparated or divorced from partner

Argued with spouse or partner more than usual

Traumatic

Became homeless

Was in a physical fight

Spouse, partner, or self went to jail

Someone very close had a problem with drinking or drugs

Financial

Moved to a new address

Lost own job

Partner lost job

Had a lot of bills they couldn’t pay

Emotional

Family member was ill or hospitalized

Were very sick themselves

Someone very close to them died8

Table 1: Specific events included in each SLE category

Presence of IPV

• PRAMS-2 asks mothers to report IPV experienced 13 to 24 months postpartum

• Five part question, which examines:– Verbal abuse (Y/N)– Limitation of contact with friends or family (Y/N)– Prevention of access to income (Y/N)– Physical Abuse (Y/N)– Sexual Abuse (Y/N)

• Mothers who answered yes to any of these types of abuse were considered to be experiencing IPV

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Additional Covariates

• Pregnancy intention• Maternal education• Maternal social support• Maternal race/ethnicity• Maternal age at birth• Maternal marital status• Urban or rural county of residence• Household’s income as percentage of the Federal

Poverty Level

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Statistical Analysis Methods

• Prevalence of depression, SLEs, IPV and other risk factors examined among all racial groups

• Bivariate logistic regression conducted to examine relationship between each risk factor and PPD among AI/AN women

• Multivariable logistic regression conducted using step-wise backwards elimination to examine risk factors for PPD among AI/AN women

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Descriptive Results

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Figure 1: Prevalence of PPD, SLEs and IPV occurring 13 – 24 months postpartum among mothers in Oregon, PRAMS-2 , 2006 & 2007

Bivariate Results

Statistically Significant Risk Factor% Depressed(weighted)

Bivariate OR(95% CI)

Stressful Life Events

Partner-related 47.5% 4.71 (2.46-9.02)

Traumatic 47.8% 3.87 (2.06-7.27)

Financial 36.9% 3.52 (1.65-7.49)

Emotional 34.3% 2.08 (1.04-4.17)

Intimate Partner Violence 54.2% 4.03 (1.95-8.35)

Other Risk Factors

Unwanted pregnancy 51.3% 3.17 (1.16-8.66)

Low social support 51.8% 3.05 (1.30-7.12)

35 years old or more 44.5% 2.37 (1.00-5.63)

Not married 37.9% 2.15 (1.16-3.99)

Less than 12th grade education 43.9% 1.57 (1.04-2.37)13

Table 2: SLEs and IPV as risk factors for PPD 13 - 24 months postpartum among AI/AN mothers Oregon , PRAMS-2 , 2006 & 2007

Bivariate Results, cont.

Statistically Significant Risk Factor% Depressed(weighted)

Bivariate OR(95% CI)

Stressful Life Events

Partner-related 47.5% 4.71 (2.46-9.02)

Traumatic 47.8% 3.87 (2.06-7.27)

Financial 36.9% 3.52 (1.65-7.49)

Emotional 34.3% 2.08 (1.04-4.17)

Intimate Partner Violence 54.2% 4.03 (1.95-8.35)

Other Risk Factors

Unwanted pregnancy 51.3% 3.17 (1.16-8.66)

Low social support 51.8% 3.05 (1.30-7.12)

35 years old or more 44.5% 2.37 (1.00-5.63)

Not married 37.9% 2.15 (1.16-3.99)

Less than 12th grade education 43.9% 1.57 (1.04-2.37)14

Table 2: SLEs and IPV as risk factors for PPD 13 - 24 months postpartum among AI/AN mothers Oregon , PRAMS-2 , 2006 & 2007

Multivariable Results

• Only partner-related SLEs and traumatic SLEs remained in the final multivariable logistic regression model

• Partner-related SLEs increase the odds ofPPD among AI/AN mothers 3.77 times (95% Confidence Interval = 1.88-7.50)

• Traumatic SLEs increase the odds ofPPD among AI/AN mothers 2.99 times (95% Confidence Interval = 1.44-5.85)

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Discussion

• Discrepancy between strongest risk factors in bivariate analysis and significant risk factors in multivariable analysis:– Might be due to colinearity between partner-

related SLEs and IPV– Might be due to small sample size of AI/AN

women, combined with underreporting of IPV

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Conclusions

• Racial disparity in adverse life events among AI/AN women:– The prevalence of PPD is extremely high– AI/AN mothers experience higher rates of SLEs

and IPV than any other racial/ethnic group

• Partner-related and traumatic SLEs are statistically significant risk factors for PPD among AI/AN women

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Strengths of Analysis

• Population based study• Minorities oversampled, including AI/AN• Data is weighted to exclude bias due to non-

response• Survey is conducted during a unique time

period, the second postpartum year, about which there is a scarcity of knowledge regarding PPD

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Limitations of Analysis

• Findings are cross-sectional:– Limited information regarding temporality– Cannot infer causality

• Several of the topics examined in this analysis, such as IPV, are very sensitive, which may lead to underreporting

• Although AI/AN women are oversampled, the sample obtained is still small, which may lead to associations being too small to detect

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Public Health Implications

• Implement interventions to prevent partner-related or traumatic SLEs among AI/AN mothers, so that the odds of PPD are decreased

• Increase screening for PPD among AI/AN mothers who have experienced partner-related or traumatic SLEs

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Thank you!

• Acknowledgment: Kathleen A. Anger, Ph.D., Office of Family Health, Oregon Public Health Division, Portland, OR

• Questions?Please contact Maria Ness:

CDC/CSTE Applied Epidemiology FellowOregon Public Health DivisionOffice of Family Health800 NE Oregon Street, Suite 825Portland OR 97232Phone: (971) 673 1564Fax: (971) 673 0240Email: maria.n.ness@state.or.us

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